Spoilers from the Dead or Alive games up to Dead or Alive 3 will be left unmarked. You Have Been Warned!

Set in the 21st century, the player controls master ninja Ryu Hayabusa. Ryu returns to his village only for it to be invaded by the fiend Doku, who takes the Dark Dragon Blade protected by the clan. After most of the clan is killed in Doku's assault, Ryu infiltrates the Vigoor Empire, for revenge and for the purpose of retrieving the Dark Dragon Blade. He must contend not only with demons and fiends, but also rival ninja clans and the Vigoor Empire's technologically advanced military.

This title marks the beginning of Tecmo's Ninja Gaiden revival series, and is set in the same continuity as Team Ninja's Dead or Alive fighting games. As a 3D action title, Ninja Gaiden sets itself apart through its elegant, finesse-focused combat and the ruthless enemies you encounter. Ryu controls very gracefully and has a number of powerful moves at his disposal, from his iconic wall running to his quick shruiken strikes. He needs them too, since the game completely averts Mook Chivalry. Enemies have no compunctions with dogpiling you, hitting you from offscreen, or even performing a Suicide Attack. Thus, the game expects the player to use every tool in their arsenal to survive and demands restraint and quick thinking. In essence, the game lets you control a master ninja, and then demands you think like one too.

It received a series of Updated Rereleases: In 2005, Ninja Gaiden Black came out for the Xbox, with additional difficulty settings (including the infamous "Ninja Dog" setting), enemies, costumes, and the missions from the downloadable "Hurricane Packs". In 2006 Ninja Gaiden Sigma came out for the PlayStation 3, with additional weapons, gameplay modes, and the inclusion of Rachel as a playable character. In 2012, Ninja Gaiden Sigma Plus was released for the PlayStation Vita. Ninja Gaiden Sigma was also included in the Ninja Gaiden Master Collection for PlayStation 4, Xbox One, Xbox Series X|S, Nintendo Switch, and PC.

A sequel, Ninja Gaiden II, was released for the Xbox 360 in 2008.

This game contains examples of:

• Advertised Extra: Ryu's childhood friend Kureha gets her own short profile in the manual of the first game, indicating she'll have some important role. In truth, she only briefly shows up in one cutscene early on before dying alongside the rest of Ryu's village.
• Artifact Mook: In the first level, Murai sends his own, novice mooks at you in normal mode. From hard mode on, though, the same level makes you fight Black Spider Ninja... which are supposed to be enemies of Murai and have no reason to obey him whatsoever. Similarly, in hard mode you will often fight fiends and Black Spider Ninja altogether, even though these fiends are supposed to fight the Ninja, not help them.
• Awesome, but Impractical:
  • The Unlabored Flawlessness. It's the wooden sword upgraded some 7 times (other weapons peak at 3 or 4) with no discernible change until it becomes a giant wooden paddle. It's a surprisingly powerful weapon, able to wreak havoc at about the same power as the upgraded War Hammer, but its high upgrade cost and very restrictive secret to its power (when you're low on health it becomes exceptionally vicious) makes it difficult to use.
  • Projectile weapons in the first Xbox game start bouncing off enemies when you get near the end (so much for your giant shuriken and stocks of gunpowder laced kunai). At that point, the primary use of the shuriken is to keep Ryu in the air and to shorten the landing animation for certain aerial attacks. The bow is an exception, but standing around for Ryu to take it out and fire gets you killed pretty quickly at higher difficulties, though it's made more useful in "Sigma Plus" as you can now shoot arrows while jumping.
• Back from the Dead: Ryu after being killed by Doku in the beginning.
• Boss Rush: Sort of, at the end. You first fight two previously beaten bosses, then Marbus, two forms of Vigoor and finally the Big Bad. At higher difficulties, the two fairly easy bosses are replaced by the much more challenging ancient fiends Nicchae and Ishtaros, making this a Boss Rush with only new bosses.
• Bragging Rights Reward:
  • In Ninja Gaiden (Sigma) for the Xbox/PS3, the Plasma Saber MK II (on Normal) or the Dark Dragon Blade (Hard and above), sort of. You get them by gathering all 50 gold scarabs, but the latter is so close to the end of the game that they won't be of much use. Add to this that you have to bring the scarabs to Muramasa, and since there's no shop at the top of the Emperor's tower (where you get the last scarab), that means you have to go backtrack through tough enemies and swarms of ghost piranhas just to find a shop where you can get the damn sword. You then discover the Plasma Saber is every bit identical to the True Dragon Sword and that you can't use the Dark Dragon Blade against the Final Boss (since he's the one using it). With the exception of some fiend challenges like the ones with many Berserkers, it's not really worth the trouble. This trope is averted with the highest difficulty Master Ninja Mode, which rewards you with...nothing!
  • The Unlabored Flawlessness can be viewed this way. Its most notable feature is that its attack power goes way up when your health is in the red zone, but if your defense is skilled enough to survive like that, you probably don't need it.
• Brutal Bonus Level: The final mission in the first game, Eternal Legend, is a mini-scenario with 5 phases, during which you face waves of all the enemies met in story mode, and several bosses in-between. You have access to most of your semi-upgraded weapons and unlimited projectiles. You can save and go shopping between phases, but you will have very limited resources, and will have to take as little damage as possible to beat the mission.
• Cannot Kill Their Loved Ones: Both Rachel and her twin sister Alma were afflicted with a blood curse that made them part fiend. While Rachel retained her humanity, the curse consumed Alma entirely. Rachel became a fiend hunter with the ultimate goal of killing her sister to free her soul. She finally finds Alma at the Dworku Monastery where she has been defeated by Ryu. However, despite this having been her motivation for being a fiend hunter, Rachel finds that she cannot bring herself to kill her own sister.
• Difficult, but Awesome: Getting the most damage out of the Unlabored Flawlessness requires Ryu to be at critically low health. If you're comfortable enough playing at such low health, you can kill everything very quickly.
• Easy-Mode Mockery:
  • In Black, dying continuously in the first level results in Ayane giving players the option of turning the difficulty down to "Ninja Dog". This results in her telling players off for giving up at "Normal" difficulty; to further the mockery, she gives players ribbons to boost stats for the rest of the play-through.
  Ayane: Master Ryu - or, should I say, Young Ninja Ryu Hayabusa - it seems I have greatly overestimated you. Oh, well. We have no choice but to proceed. I will support you in every way I can. Don't be overconfident; just do what I say and perform your duties as competently as you can. You must complete your task without fail.
  • Averted with the "Hero Mode", in this difficulty setting, the game will help the players by automatically block incoming attacks and giving infinite uses of Ninpo should Ryu's health ran low, and in "Hero Mode", the player can still reach ranks like Head Ninja or Master Ninja.
• Embedded Precursor: The original Ninja Gaiden (NES) trilogy is an unlockable in the original Xbox version. The Black version, meanwhile, instead has the arcade version.
• Energy Weapon : Paz Zuu uses Eye Beams which, oddly enough, doesn't damage you directly; instead, it traces a path, which ignites shortly afterwards. Unfortunately, the black pincer fiends in the same game aren't so kind-hearted with their own Eye Beams, infuriating more than one player.
• Faux Action Girl: Rachel, who kills a random fiend when she's introduced, spends the rest of the game getting captured, thrown around Vigoor and being strung up for a sacrifice. Lovely outfit, however. This gets fixed in Sigma, where she's promoted to playable character, thus promoted to full-on Action Girl. Who still gets constantly captured and thrown around in the cutscenes. Aside from the promotion, her role in the story didn't change.
• Fetch Quest: The golden scarabs.
• Grenade Launcher: Certain MSAT mooks carry these, and Black gave the tanks these to counter an easy means of defeating them, which was to get so close that it could only circle without being able to fire its cannon, only a mounted machine gun with a suppressible gunner.
• Hard-Mode Mook: Black, and by extension Sigma, has the Ryu clones, mini-bosses who appear unexpectedly where you fought common enemies in Normal mode. Then in Very Hard, you meet a new type of Black Spider ninjas throwing Fuuma Shurikens at you. And then in Master Ninja mode, you meet yet another type with swords that literally burn you when they hit you. Hard mode and above also put you against tougher versions of the cops and soldiers, specially immune to some of your techniques.
• Hopeless Boss Fight: Two of them in Sigma. In Chapter 2 against Doku, when you have only a level one Dragon Sword and a tiny lifebar, and in Chapter 14 with Rachel when you fight Nicchae and Ishtaros. In both cases, a normal player will likely get their ass handed before understanding what's going on. It is technically possible to win, but that requires insane skill, and even if you do your character gets beaten in the cutscene anyway. Beating the Chapter 2 fight on Hard and Very Hard unlocks the next difficulty early.
• Mask Power: Inverted with the Ogres, who grow stronger after Ryu breaks their masks.
• Mighty Glacier: Combined with Stone Wall, The purple zombies. They carry enormous bayonet guns, their attacks are pretty damaging, but are so slow you have to be really careless to get killed. It takes three full Ultimate Techniques of the Unlabored Flawlessness to make them bite the dust, meaning they have more health than some bosses.
• Mook Bouncer: The black laser fiends in the first Xbox game are already annoying, but in the tower section of the second-to-last chapter, they can use a really nasty grapple that drags you underground and sends you back to the level below, forcing you to go through the previous wave of enemies again and through a wave of ghost fish. Even more infuriating if you're doing a Karma run, since it prevents you from getting any more points in that fight (it's counted as if you had fled the fight).
• Mysterious Watcher: The Dark Disciple spends most of the story observing Ryu, only springing into action after Ryu gets the Dark Dragon Blade back.
• Nerf: The Flying Swallow in the Xbox game was toned down in Black because you could spam it on pretty much everything with 100% success. Black featured mooks that were specifically designed to punish you for overabusing it, i.e. block the attack entirely and counter it. You definitely didn't want to be caught using that on the Advanced MSAT soldiers.
• Non-Standard Game Over: In the first game, after you get the bow, you can use it to shoot a wounded Ayane dead; the game will promptly end as a result.
• One-Time Dungeon: You can't go back to the Ninja Fortress from Chapter 1 nor enter the airship in Chapter 3 since it crashes.
• Spy Catsuit: Ryu's new design for this game, coupled with a Scarf of Asskicking and a Cool Mask to boot.
• Thriving Ghost Town: Tairon, capital of the Vigoor Empire, doesn't seem to have anyone other than a lone shopkeeper, a busty dominatrix, and a bunch of military personnel. Subverted when there are people in the nightclub, but they all run screaming when a giant dinosaur-fiend shows up. That, and the Vigoorian military imposes a curfew more or less as soon as Ryu shows up.
• Temporary Online Content: The Hurricane Packs for the original Xbox game, following the discontinuation of the original Xbox Live service. While Ninja Gaiden Black carries over most of the content from the Hurricane Packs (extra game modes and costumes), it also removes the famed Intercept move, which was deemed too powerful by the developers.
• Unexpected Gameplay Change: The Emperor is fought on a floating platform that you must move back and forth (default) or up and down (by holding the guard button) to avoid its Beam Spam. It's painfully unintuitive and tedious.
• Unexplained Recovery: Earlier, at the end of the second chapter of the first game, Ryu is clearly killed, but the next scene has him gearing up for battle as if it never happened, and it's never mentioned again.
• Very Definitely Final Dungeon: The Imperial Palace. It's an enormous tower hanging upside down and covered in giant skulls. It's so very definitely final, that even the item chests are evil and spiky.
• Video Game Cruelty Punishment: Shoot a wounded Ayane with your newly-acquired bow, and the game immediately ends in failure.
• Wake-Up Call Boss: Murai, the very first boss of the game, is a classic example of this. For basically the entire level, you're mostly fighting enemies that can be dispatched relatively easily. Murai, on the other hand, is vulnerable far less often and heavily punishes players who go in at the wrong times or get caught by his attacks, dealing large amounts of damage that can kill a player quickly if they aren't careful.